from bisect import *

N, K = map(int, input().split())
A = list(map(int, input().split()))
A.sort()
mod = 10**9 + 7
ans = 1
for i in range(N//2):
    ind = bisect_right(A, K - A[-1-i])
    ans *= min(N - 1 - i, ind) - i
    ans %= mod
    
print(ans)